Method and apparatus for opening multifilament tows



6- G. ZEIDMAN Oct. 27, 1970 METHOD AND APPARATUS FOR OPENING MULTI- FILAMENT TOWS Filed Sept. l8, 1967 2 Sheets-Sheet 1 FIG.|.

FIG.3

GORDON G. ZEIDMAN INVENTOR.

Oct. 27, 1970 5, z M 3,535,745

7 METHOD AND APPARATUS FOR OPENING MULTI-FILAMENT TOWS Filed Sept. 18, 1967 2 Sheets-Sheet 2 MW AW m MT FIG.9

United States Patent 3,535,745 METHOD AND APPARATUS FOR OPENING MULTIFILAMENT TOWS Gordon G. Zeidman, Columbus, Ohio, assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed Sept. 18, 1967, Ser. No. 668,589 Int. Cl. D01b 3/10 U.S. Cl. 19-65 2 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for opening and blooming an initially compact multifilament tow. A banding and blooming jet including a tow passage bounded above by a generally flat plate having formed therein a plurality of air flow orifices having their axes arranged in a zig-zag pattern and inclined downwardly and outwardly to direct air transversely across the path of the tow. The axes of the orifices may have a component in the direction of movement of the tow to enhance the blooming effect. The method includes the use of a very low pressure stream of air on the order of 3 to 40 inches of water pressure.

The present invention relates to a method and apparatus for processing of textile filaments, and more particularly to the removal of shiners or married fibers in the tow, The term tow is used to designate a strand of yarn composed of a large number of individual continuous filaments. A single tow may usually consist of 500 to 5,000,000 single filaments which range in size from a fraction of a denier to 30 denier per filament. The words shiners or married fibers are used in the present instance to describe the condition where two or more filaments are stuck together and are not easily separated in textile processing. When tow is converted to various fiber lengths, if the shiners are not removed a staple of poor openness results, the disadvantages of which will be readily apparent to those in the art.

The concept of improving the openness of multifilament tow is not new. Early procedures for Opening tow included the use of picking and carding machines. More recent methods and apparatus for obtaining this result include passing the tow through a device called a banding jet wherein air under pressure is passed through jet passages into a moving tow for the purpose of blowing the filaments apart into the form a more or less fiat band. An example of a previously known banding jet is shown in the patent to Jackson, No. 2,737,688, issued Mar. 13, 1956.

It is believed that the presently known banding jet tow opening devices perform satisfactorily. However, there still exists a need to provide improved methods and banding jet apparatus to increase the operating economy and efficiency of the tow opening procedures.

Thus, it is a purpose of the present invention to provide a method and apparatus relating to a banding jet, which represents a substantial improvement over previously known banding jets in terms of operating efficiency and economy.

An important factor in the operating efficiency and economy of a banding jet is the quantity and pressure of the air supplied to the banding jet to perform the tow opening function. High pressure air requires a more expensive air supply means and more expensive fittings to ensure that the high pressure is maintained in the system. It has been thought heretofore that the high pressure was essential in order for the air stream to carry out its tow opening function. In the method of the present invention ice the stream of air is at much lower pressure than has been thought practical heretofore. The banding jet orifice plate is so constructed that tow opening may be carried out effectively and economically while using air at a very low pressure, for example, between zero and one p.s.i.g. while retaining at least the same, if not an improved, separation of the tow filaments as compared to high pressure techniques.

According to the apparatus of the present invention there is provided a tow opening device including a tow passage bounded on one side by a banding jet in the form of a generally flat orifice plate through which the low pressure air passes from an air source to the moving tow. The orifice plate of the present invention includes a plurality of apertures, the axes of which extend at an angle inclined downwardly and transversely across the path of movement of the tow. The orifice axes may lie in planes perpendicular to the direction of movement of the tow or they may extend at an angle relative to that direction resulting in an air flow component extending in the tow movement direction and causing an alternating tow speed variation within the banding unit. Such a speed variation enhances the opening or banding of the tow and can result in some tow blooming. The plate will generally include two groups of orifices, one directed to a first side of the tow and the other directed to the opposite side of the tow. It is preferred that the orifices of the two groups be interspersed throughout the plate so that all portions of the tow passing through the passage will be subjected to streams of air from each of the two groups of orifices.

Thus, it is an object of the present invention to provide a tow opening device which is substantially improved relative to tow opening devices known heretofore.

It is still another object of this invention to provide a tow opening device including a banding jet which directs air transversely across the path of movement of the tow.

It is still another object of this invention to provide an apparatus which will effectively open a tow with air streams at a pressure less than 1 p.s.i.g.

It is still another object of this invention to provide a method for opening tow efficiently and economically with the use of low pressure air.

Other objects and the attendant advantages of the present invention will become apparent from the detailed description to follow together with the accompanying drawings which illustrate a preferred embodiment of the invention.

There follows a detailed description of the present invention to be read together with accompanying drawings. However, it is to be understood that the detailed description and the accompanying drawings are intended only to illustrate preferred embodiments of the invention and that the invention is capable of numerous modifications and variations apparent to those skilled in the art without departing from the spirit or scope of the invention as defined in the appended claims.

In the drawings:

FIG. 1 is a perspective view of a typical tow opening device in which a banding jet orifice plate constructed in accordance with the present invention would be mounted.

FIG. 2 is a transverse sectional view taken along line 2-2 of FIG. 1.

FIG. 3 is a longitudinal sectional view taken along line 33 of FIG. 1.

FIG. 4 is a partial horizontal sectional view taken along a plane including line 44 of FIG. 1.

FIG. 5 is a partial sectional view of the plate of FIG. 4 taken along line 5-5 of FIG. 4.

FIG. 6 is a partial sectional view of the plate of FIG. 4 taken along line 66 of FIG. 4.

FIG. 7 illustrates a modified construction of the orifice plate shown in the embodiment of FIGS. 1-6.

FIG. 8 is a partial sectional view taken along line 88 of FIG. 7.

FIG. 9 is a partial sectional view taken along line 9-9 of FIG. 7.

Referring now to the drawings, and in particular to FIGS. 16 there is shown a banding jet type tow opening device 10 for separating the filaments of a multi-filament tow 11. The device includes a top member 12 in communication with an air inlet passage 21. The bottom of the device is closed off by an imperforate bottom plate 13 and the sides are closed off by side plates 14 and 15. The device is divided by a horizontal, substantially fiat orifice plate 17 into an upper portion and a lower portion. The upper portion is a plenum chamber 16 formed by the top of plate 17 together with the side plates 14 and and the top plate 12. The lower portion below the plate 17 is a tow passageway 18 formed by the bottom of plate 17 together with bottom plate 13 and side plates 14 and 15. The passageway 18 has a rectangular inlet opening 19 and a rectangular outlet opening 20 for the introduction and discharge of the multi-filament tow.

An important feature of the invention is the specific construction of the orifice plate 17. Referring first to the embodiment of FIGS. 1-6, the orifices 22 extend through the orifice plate 17 and provide conduits connecting the plenum chamber 16 with the tow passageway 18. Referring in particular to FIG. 4, it can be seen that adjacent rows of the orifices 22 extend downwardly in opposite directions. Further, the orifices in adjacent rows are offset from one another. That is, the orifices in the first, third and fifth rows extend downwardly (into the paper) to the right while the orifices of the second and fourth rows extend downwardly (into the paper) to the left and the orifices in the first, third and fifth rows are aligned but not with the orifices of the second and fourth rows. This arrangement assures that all strands of a multifilament tow passing through the passageway 18 will be subjected to transversely directed streams of air in both directions. One result of this feature is that it permits operation of the device and effective opening of the tow with very low pressure air streams.

FIGS. 2 and 3 show the rows of apertures with eleven apertures in each row. In practice, however, the number of rows and the number of orifices in each row can be varied at will depending only upon the particular size of the plate and the size of the passage. Two plates which have been employed successfully in practice are first, an eight inch 88 hole plate having eight rows with eleven orifices in each row (as shown in the drawings) and a ten inch 130 orifice plate having ten rows and thirteen orifices in each row.

FIGS. 79 illustrate another embodiment of the invention. While in the embodiment of FIG. 4 the inclined axes of the orifices 22 lie in reference planes perpendicular to the direction of movement of the tow, in the embodiment of FIGS. 7-9 the axes of the orifices 22 lie in planes rotated from that plane perpendicular to the direction of tow movement by an angle 6 which may be, for example, ten degrees. As in the first embodiment, alternate rows face towards opposite sides of the plate. FIG. 8 illustrates a first orifice 22 extending downwardly (into the paper) to the left and FIG. 9 illustrates a second orifice 22 extending downwardly (into the paper) and to the right.

The important features of the invention which provide the new and unobvious results of an economical low pressure chamber have been described in detail above. However, for purposes of illustration, specific data and a specific illustration of the invention will be set forth below.

First, the air pressure should be very low, normally below one pound per square inch gauge. A normal range of operation is from 4 /2 to inches of water although a preferred range would be between 4 /2 and 9 inches of water. A more important factor from the standpoint of operation is air consumption which is, of course, related to pressure. In fact, it has been found that air consump tion is quite low, even lower than what would be anticipated from theoretical calculations. When using an 88 hole jet orifice it was found that 'air consumption varied linearly from about 60 to cubic feet per minute when the air pressure increased from 5 to 20 inches of water. Using a 10 inch hole jet orifice it was found that air consumption varied linearly from about 78 to cubic feet per minute as the pressure was increased from 10 to 40 inches of water.

The shape of the orifices is not necessarily critical although it would be limited by practical manufacturing considerations. The angle of inclination oz and a relative to the plane of plate 17 of orifices 22 is about 30", this angle having been chosen since it provides the desired spacing between holes within a row. Aside from manufacturing considerations a range of angles for this component could include anything above zero degrees relative to plate 17 so that at least some component trans verse of the direction of tow movement would be provided. Below 15 it is very difficult to drill a hole in a fiat plate. Also, hole spacing would be relatively large.

In the second embodiment of the invention, as shown in FIGS. 7-9, it is believed that an angle 0 of 10 allows desirable spacing between the rows of holes. An angle greater than 10 would necessitate a greater distance and vice-versa for angles less than 10. From a manufacturing standpoint a practical range might be between a 5 and 50.

In experiments conducted with this device it has been found that the banding jet device would work satisfactorily to process tow bands with a total denier range from 30,000 to 90,000 within a denier per filament range of 1.6 to 25. Certain dimensions may have to be changed in order to handle items with total denier greater than about 60,000. For example, the distance between the orifice plate and the opposite backup plate 13 would have to be increased to allow the tow band to pass through easily.

It is apparent that by following the teachings of the above described invention, an efiicient banding jet can be produced. Low pressure and relatively low volume air or other gas can achieve satisfactory banding in the device according to this invention because the orifices connecting the source of air to the tow passageway are inclined in different directions in alternate rows with respect to the plane of the tow and tow passageway, and offset from one another in alternate rows. Thus, each filament of the tow is, because of the offsetting of the orifices, subjected to a flow of air from several orifices as it passes through the tow passageway. Because of the incliniation of the orifices the tow is caused to open first in one transverse direction and then in the other as it is passed through the banding jet passageway. These alternating changes in direction aid greatly in tow opening or banding.

Further efiiciencies and advantages are added to the banding jet according to this invention by inclining the orifices relative to the transverse direction of the tow to produce an air stream component parallel to the direction of tow movement. Because of this arrangement the tow is subjected to forces which alternately tend to speed it up and slow it down. Again such action aids in tow opening and also produces a degree of blooming depending on the pressure of the impinging gas passed through orifices 22.

The invention has ben described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

Way downwardly at an angle of approximately 30 relative to said flat side with the axes of said orifices lying in planes rotated from reference planes perpendicular to the direction of tow movement by an angle in the range of from about 5 to about 50,

generally rectangular cross-section taken in a plane substantially perpendicular to the direction of movement of the tow which cross-section has a width whereby a component of the stream of gas through said orifices will be in the direction of movement of said tow.

'2. Apparatus as set forth in claim v1 wherein the axes of said orifices lie in planes rotated from said reference planes about 10.

greater than its height, and

a plate having at least one generally flat side defining one of the sides of said pasageway, said plate including a plurality of rows of orifices arranged with orifices immediately adjacent one another in the direction of movement of the tow transversely oifset from one another relative to said direction of movement, 15

References Cited UNITED STATES PATENTS each row of orifices extending across the plate trans- 3,226,773 19 6 Pa iyenko 19-66 verse to the direction of movement of the tow and 3,333,315 8/1967 y ell 281 XR the orifices in each row being inclined in the same 3,345,697 967 Aspy 19-66 direction and offset transversely relative to the ori- 3,444,592 5/1969 weigand 19-66 fices in adjacent rows, the orifices in alternate rows 20 being inclined toward opposite sides of the passage- DORSEY NEWTON Pnmary Exammer 

